JP2019006963A - Manufacturing method of composite resin particle, resin molded body, and composite resin particle - Google Patents

Abstract

To manufacture a composite resin particle with maintaining physical properties originally obtained by PTFE derived from a fine powder.SOLUTION: There is selected a manufacturing method of a composite resin particle including a first process for cracking a fine powder containing PTFE obtained by an emulsion polymerization in the presence of a ketone-based solvent, a second process for dispersing the cracked fine powder, a carbon nanomaterial in the ketone-based solvent to obtain a composite resin particle dispersion, and a third process for removing the ketone-based solvent from the composite resin particle dispersion to obtain a composite resin particle, in which the fine powder is cracked to have average particle diameter of 50 μm or less in the first process, and a temperature of the ketone-based solvent is 20°C or less.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing composite resin particles, a resin molded body, and composite resin particles.

  Carbon nanomaterials such as carbon nanotubes (hereinafter also referred to as “CNT”) are excellent in various physical properties such as crystallinity, conductivity, and thermal conductivity, and are widely put into practical use. Composite resin particles containing a carbon nanomaterial and a resin material are used in molded articles used for electronic parts, automobile parts, and the like.

As an example of the resin material, there is polytetrafluoroethylene (hereinafter also referred to as “PTFE”) which is a polymer of tetrafluoroethylene (hereinafter also referred to as “TFE”). PTFE is a resin excellent in moldability and excellent in mechanical strength, heat resistance, flexibility and the like.
However, since PTFE is electrically insulating, it is necessary to impart conductivity depending on the application.

Therefore, in order to impart conductivity to PTFE using the excellent conductivity of the carbon nanomaterial, development of composite resin particles containing the carbon nanomaterial and PTFE has been performed (Patent Document 1).
Patent Document 1 discloses a composite resin particle dispersion obtained by dispersing PTFE powder called a molding powder having a particle size of about 1 to 100 μm and CNT having a length of about 1 to 100 μm in a ketone solvent or the like. And a method for producing a composite resin particle by removing a ketone solvent or the like from the composite resin particle dispersion. The molding powder is a powder containing PTFE obtained by suspension polymerization of TFE.

PTFE powder includes fine powder in addition to molding powder. The fine powder is a powder containing PTFE obtained by emulsion polymerization or the like of TFE. In general, the fine powder has a particle size of about 500 μm, which is larger than the particle size of the molding powder, and is unsuitable for forming carbon nanomaterials and composite resin particles.
However, the fine powder is easy to handle when performing operations such as drying, weighing, packing, and transferring, and is easy to handle in the process of mixing the auxiliary agent during extrusion and filling the mold.
Patent Document 2 discloses a method of pulverizing such fine powder together with a filler in the presence of carbon dioxide gas, and uniformly mixing the fine powder and the filler to obtain an aggregate of PTFE and filler. . Patent Document 2 discloses a method of producing a molding powder having a desired particle size by adding a solvent to the aggregate obtained by the above method and moistening it.

Japanese Patent Laying-Open No. 2015-30821 JP-A-2015-151543

However, even if the technique described in Patent Document 1 is applied to fine powder, CNTs are unlikely to adhere to the surface of the fluororesin particles. This is because the surface of the fluororesin powder of the fine powder has less irregularities than the molding powder and has a large particle size, that is, the specific surface area of the fluororesin particles that can come into contact with the CNT is small. Since the CNTs hardly adhere to the surface of the fluororesin particles, there are many CNTs that do not adhere to the surface of the fluororesin particles. Therefore, in the composite resin particles obtained by collecting and drying the mixed slurry of the CNT dispersion liquid and the fluororesin powder, a large number of CNTs remaining without adhering are mixed.
From the above, the composite resin particle molded body obtained by the method described in Patent Document 1 has defects such as cracks due to the aggregates of CNTs. Further, the mechanical properties of such a molded body are remarkably lowered, and the conductivity of the molded body is also unstable.

The method described in Patent Document 2 is a method for producing composite resin particles containing a filler by so-called dry mixing. However, the dry mixing does not disperse the CNT bundle, and the filler and fine powder cannot be combined at the monodisperse level. Therefore, even if the composite resin particles are produced by the method of Patent Document 2 with the concentration of CNT being about 0.2% by mass, conductivity or the like cannot be imparted to the composite resin particles.
Further, in the method described in Patent Document 2, a large amount of graphite powder of 30% by mass is used. Therefore, the composite resin particle molded body obtained by the method has low physical properties such as flexibility.
From the above, the method described in Patent Document 2 cannot achieve the desired conductivity unless a large amount of CNT is used, and the fine powder originally possessed by using a large amount of CNT, etc. Superior properties are reduced.

  This invention is made | formed in view of the said situation, Comprising: It aims at manufacturing the composite resin particle by which the original physical property of PTFE derived from fine powder was maintained.

The present invention has the following configuration.
[1] A first step of pulverizing a fine powder containing polytetrafluoroethylene obtained by emulsion polymerization in the presence of a ketone solvent; the pulverized fine powder; and a carbon nanomaterial. A first step of obtaining a composite resin particle dispersion by dispersing in a system solvent, and a third step of obtaining a composite resin particle by removing the ketone solvent from the composite resin particle dispersion. And crushing the fine powder to an average particle size of 50 μm or less, and setting the temperature of the ketone solvent to 20 ° C. or less.
[2] The concentration of the carbon nanomaterial is 0.01 to 0.5% by mass with respect to a total of 100% by mass of the carbon nanomaterial and the fine powder. A method for producing composite resin particles.
[3] The composite resin particle according to [1] or [2], wherein the ketone solvent includes at least one selected from the group consisting of methyl ethyl ketone, acetone, diethyl ketone, methyl propyl ketone, and cyclohexanone. Manufacturing method.
[4] The method for producing composite resin particles according to any one of [1] to [3], wherein the carbon nanomaterial is a carbon nanotube.
[5] A resin molded body molded using the composite resin particles produced by the method for producing composite resin particles according to any one of [1] to [4].
[6] Composite resin particles containing fine powder-derived polytetrafluoroethylene containing polytetrafluoroethylene obtained by emulsion polymerization and a carbon nanomaterial, and the volume resistivity of the composite resin particles is 1.0 × Composite resin particles of 10 ⁹ Ω · cm or less.

  ADVANTAGE OF THE INVENTION According to this invention, the composite resin particle in which the carbon nanomaterial adhered uniformly to PTFE derived from fine powder can be manufactured, maintaining the physical property of PTFE derived from fine powder.

The following definitions of terms apply throughout this specification and the claims.
The “average particle size” is a value measured using a particle size distribution meter.
The “volume resistivity” is a value measured by a four-terminal method using a resistivity meter (“Loresta GPMCP-T610 type” manufactured by Mitsubishi Chemical Analytech Co., Ltd.).
“Composite resin particle dispersion” means a dispersion of composite resin particles in a liquid medium.
“Composite resin particles” mean composite particles comprising a resin and a carbon nanomaterial.

[Production method of composite resin particles]
Hereinafter, the manufacturing method of the composite resin particle which is one Embodiment to which this invention is applied is demonstrated. The method for producing composite resin particles of the present embodiment includes a first step, a second step, and a third step. The first step is a step of crushing fine powder containing polytetrafluoroethylene obtained by emulsion polymerization (hereinafter sometimes simply referred to as “fine powder”) in the presence of a ketone solvent. The second step is a step of obtaining a composite resin particle dispersion by dispersing the pulverized fine powder and the carbon nanomaterial in the ketone solvent. The third step is a step of obtaining the composite resin particles by removing the ketone solvent from the composite resin particle dispersion.

In the method for producing composite resin particles of the present embodiment, the first step is performed before the second step, the average particle size of the fine powder is crushed to 50 μm or less in the first step, and the first step In the step, the temperature of the ketone solvent is set to 20 ° C. or lower.
Hereinafter, the method for producing composite resin particles according to the present embodiment will be described in detail in the order of each step.

(First step)
Hereinafter, the 1st process of the manufacturing method of the composite resin particle of this embodiment is demonstrated.
The first step is a step of crushing the fine powder in the presence of a ketone solvent.
Examples of the ketone solvent include, but are not limited to, methyl ethyl ketone, acetone, diethyl ketone, methyl propyl ketone, and cyclohexanone. As a ketone solvent, what was synthesize | combined may be used and a commercial item may be used.

Fine powder is a powder containing PTFE obtained by emulsion polymerization. Such fine powder can be synthesized by a known method. The method for synthesizing the fine powder is not particularly limited. As an example, particles having a size of about several hundred μm are obtained by emulsion-polymerizing TFE using a stabilizer and an emulsifier, and agglomerating particles in the reaction solution obtained by emulsion polymerization. There are ways to dry.
As fine powder, what was synthesize | combined may be used and a commercial item may be used.
Examples of commercially available fine powder include “PTFE fine powder grade F-104 (average particle size: about 500 μm)” manufactured by Daikin Industries, Ltd., but are not limited thereto.

Fine powder can be crushed by applying mechanical energy.
Generally, the molecular chain of PTFE contained in fine powder is folded by emulsion polymerization at the time of production. The molecular chain of such fine powder tends to open like a fiber under conditions higher than 20 ° C. When the molecular chain opens like a fiber, properties such as physical properties derived from PTFE inherent to the fine powder are changed.

The first step of the method for producing composite resin particles of the present embodiment is characterized in that the shearing force applied to the fine powder during crushing is suppressed. By suppressing the shear force, heat generated during shearing can be reduced, and the folded structure of the molecular chain of PTFE can be maintained.
The method for crushing the fine powder is not particularly limited as long as the shearing force applied to the powder particles of the fine powder is suppressed. Examples of the pulverization method include, but are not limited to, stirring using a stirrer, pulverization using ultrasonic waves, and pulverization using a known pulverizer such as a food processor.

  Although the average particle diameter of the fine powder as a raw material cannot be generally stated, it is preferably about 400 to 500 μm from the viewpoint of workability in the crushing process. When the average particle size of the fine powder is about 400 to 500 μm, it is not necessary to give an excessive amount of energy to the fine powder during crushing, and it becomes easy to crush to a predetermined average particle size.

  In the first step of the method for producing composite resin particles of this embodiment, the fine powder has an average particle size of 50 μm or less. By crushing the average particle size of the fine powder to 50 μm or less in the first step, the irregularities on the surface of the fluororesin particles of the fine powder increase, the specific surface area increases, and the surface that can come into contact with the carbon nanomaterial increases. As a result, the probability of contact with the carbon nanomaterial increases, and the amount of the carbon nanomaterial that can be adsorbed on the surface of the fine powder particles tends to increase. Therefore, when the average particle size of the fine powder is 50 μm or less, the carbon nanomaterial can be easily adsorbed and impregnated on the surface of the fine powder, and the aggregates of the carbon nanomaterial can be easily reduced.

  In the first step of the method for producing composite resin particles of the present embodiment, it is preferable that the fine powder has an average particle size of 5 μm or more. If the average particle size of the fine powder is crushed to 5 μm or more in the first step, the specific surface area of the fine powder does not increase excessively, and the amount of the carbon nanomaterial relative to the fine powder is unlikely to be insufficient. Therefore, in the area | region of the surface of fine powder, the distribution of the area | region which the carbon nanomaterial adsorb | sucked and the area | region which is not adsorb | sucking is difficult, and it becomes easy to stabilize electroconductivity. From the above, if the average particle size of the fine powder is crushed in the range of 5 μm to 50 μm in the first step, the carbon nanomaterial can be uniformly attached to the surface of the fine powder, the appearance uniformity is high, and It is easy to produce composite resin particles capable of obtaining a molded article having good conductivity.

  In the first step of the method for producing composite resin particles of this embodiment, the temperature of the ketone solvent is set to 20 ° C. or lower. In another example of the method for producing composite resin particles of the present embodiment, the temperature of the ketone solvent is set to 10 ° C. or lower in the first step. By setting the temperature of the ketone solvent to 20 ° C. or lower in the first step, it is possible to produce composite resin particles in which the carbon nanomaterial is uniformly attached to the fine powder while maintaining the excellent physical properties of the fine powder.

  Since the 1st process of the manufacturing method of the composite resin particle of this embodiment is performed in presence of a ketone solvent, it can mix by wet. Since the fine powder can be crushed at 20 ° C. or lower by cooling the ketone solvent, the method for producing the composite resin particles of the present embodiment is a simpler method than the case of cooling the fine powder by dry mixing. It is. An example of a method for setting the temperature of the ketone solvent to 20 ° C. or lower includes an ice bath, but is not particularly limited.

  In the method for producing composite resin particles of this embodiment, the first step is performed before the second step. By performing the first step before the second step, the carbon nanomaterial used in the second step can easily adhere uniformly to the surface layer of particles made of PTFE in the fine powder, and the carbon nanomaterial is fixed to the fine powder. can do. Thereby, the dispersibility of the composite resin particle dispersion obtained in the second step is improved.

  In the method for producing composite resin particles of the present embodiment, in the first step, by selecting an appropriate crushing method, the fine powder can be crushed to 50 μm or less without causing molecular chains of the fine powder to be fibrillated. Can do. Therefore, the carbon nanomaterial can easily adhere to the fine powder uniformly while maintaining the excellent physical properties of the fine powder.

  In an example of the method for producing composite resin particles of the present embodiment, in the first step, resin slurry in which fine powder is dispersed in a ketone solvent by crushing fine powder in the presence of a ketone solvent. Can be obtained.

(Second step)
Hereinafter, the 2nd process of the manufacturing method of the composite resin particle of this embodiment is demonstrated.
The second step is a step of obtaining a composite resin particle dispersion by dispersing the fine powder crushed in the first step and the carbon nanomaterial in a ketone solvent. The composite resin particles are composite resin particles produced in the second step. The composite resin particles include fine powder-derived PTFE and a carbon nanomaterial. The composite resin particle dispersion is a liquid in which composite resin particles containing PTFE derived from fine powder and a carbon nanomaterial are dispersed in a ketone solvent.

The carbon nanomaterial is a material formed from an aligned carbon six-membered ring structure. The average length of the carbon nanomaterial cannot be generally specified, but is preferably 10 to 600 μm. If the average length of the carbon nanomaterial is equal to or greater than the lower limit, the resulting composite resin particles are likely to have excellent conductivity. If the average length of the carbon nanomaterial is equal to or less than the upper limit value, the carbon nanotubes are likely to adhere uniformly to the resulting fine powder.
Examples of the carbon nanomaterial include, but are not limited to, carbon nanofiber, carbon nanohorn, carbon nanocoil, graphene, fullerene, acetylene black, ketchon black, carbon black, and carbon fiber.

  In the composite resin particles produced in the second step of the method for producing composite resin particles of the present embodiment, the carbon nanomaterial is preferably uniformly attached to the surface layer of particles containing PTFE derived from fine powder. Thereby, excellent properties derived from PTFE such as moldability and mechanical properties can be maintained, and the conductivity of the composite resin particles can be stabilized.

  In an example of the method for producing composite resin particles of the present embodiment, the carbon nanomaterial used in the second step may be dispersed in a ketone solvent. Examples of the carbon nanomaterial used in the second step include a CNT dispersion liquid in which CNT, which is a carbon nanomaterial, is dispersed in a ketone solvent such as methyl ethyl ketone (hereinafter also referred to as “MEK”). Good.

  In an example of the method for producing composite resin particles of the present embodiment, the resin slurry obtained in the first step and the CNT dispersion may be mixed in the second step. Thereby, a composite resin particle dispersion can be obtained.

  In an example of the method for producing composite resin particles of this embodiment, a composite resin particle dispersion may be obtained by so-called wet mixing. If wet mixing is performed, the bundle of carbon nanomaterials can be easily dispersed, and the fine powder-derived PTFE and the carbon nanomaterial can be combined in a state close to monodispersion.

  In an example of the method for producing composite resin particles of the present embodiment, the carbon nanomaterial can be uniformly attached to the surface layer of PTFE resin particles derived from fine powder in a state close to monodispersion, and can be fixed. Therefore, in an example of the method for producing composite resin particles of the present embodiment, conductivity can be imparted to the composite resin particles even when an extremely low concentration of carbon nanomaterial is used.

In an example of the manufacturing method of the composite resin particle of this embodiment, the density | concentration of carbon nanomaterial is 0.01-0.5 mass% with respect to a total of 100 mass% of carbon nanomaterial and fine powder. If the density | concentration of a carbon nanomaterial is more than the said lower limit, it will be easy to provide electroconductivity to a composite resin particle. If the concentration of the carbon nanomaterial is not more than the above upper limit value, excellent physical properties such as fine powder moldability and mechanical properties can be maintained as they are.
In an example of the method for producing composite resin particles of the present embodiment, by using a very small amount of carbon nanomaterial with respect to the fine powder, conductivity is imparted to the obtained composite resin particles, and the moldability of the fine powder is increased. Excellent physical properties such as mechanical properties can be maintained as they are.

  In the semiconductor field, there is a strong demand for reducing filler dust generation and outgassing. According to the example of the method for producing composite resin particles of the present embodiment described above, the amount of carbon nanomaterial used is small, so that the risk of contamination caused by the carbon nanomaterial in the production process can be reduced.

  In the second step of an example of the method for producing composite resin particles of the present embodiment, a known dispersant is used when the fine powder crushed in the first step and the carbon nanomaterial are dispersed in the ketone solvent. May be. Examples of the dispersant include known dispersants such as acrylic dispersants, but are not limited thereto.

(Third process)
Hereinafter, the 3rd process of the manufacturing method of the composite resin particle of this embodiment is demonstrated.
The third step is a step of obtaining the composite resin particles by removing the ketone solvent from the composite resin particle dispersion prepared in the second step. The method for removing the ketone solvent from the composite resin particle dispersion may be a known solvent removal method such as solid-liquid separation, and is not particularly limited.

In an example of the method for producing composite resin particles of the present embodiment, the composite resin particle dispersion can be supplied to a spray dryer apparatus by a slurry pump and dried to obtain composite resin particles. The dried powder can be collected to obtain composite resin particles.
The composite resin particle dispersion may be dried by a known drying method such as vacuum drying, heat drying, and natural drying, and the drying method is not limited thereto.

(Function and effect)
According to the composite resin particle manufacturing method of the present embodiment described above, since the first step is performed before the second step, it is possible to manufacture composite resin particles in which the carbon nanomaterial is uniformly attached to the fine powder. it can.
Further, according to the method for producing composite resin particles of this embodiment, the fine powder has an average particle size of 50 μm or less in the first step and the temperature of the ketone solvent is 20 ° C. or less. It is possible to prevent the molecular chain from opening in the form of a fiber, and the physical properties of the fine powder are hardly impaired.
Further, in the method for producing composite resin particles of the present embodiment, in order to prevent the formation of CNT aggregates, before mixing the fine powder and the CNT, the fine powder is crushed to an average particle size of 50 μm or less. ing. Therefore, according to the method for producing composite resin particles of the present embodiment, the unevenness of the surface of the fine powder is increased, the area that can adsorb CNTs is increased, and CNTs are easily adhered uniformly.
Therefore, according to the manufacturing method of the composite resin particle of this embodiment, the composite resin particle in which the original physical property of PTFE derived from fine powder is maintained can be manufactured.

[Resin molding]
Hereinafter, a resin molded body which is an embodiment to which the present invention is applied will be described.
The resin molded body of the present embodiment is a resin molded body molded using the composite resin particles manufactured according to the description in the section “[Method of manufacturing composite resin particles]” of the present embodiment described above.
In such composite resin particles, the carbon nanomaterial is uniformly attached to PTFE derived from fine powder. Therefore, the resin molded body of this embodiment can have excellent appearance uniformity in addition to excellent physical properties derived from fine powder such as moldability and mechanical properties.
According to the resin molded body of the present embodiment, it is possible to uniformly disperse the carbon nanomaterial with respect to PTFE derived from fine powder, which has been difficult in the past, and a flexible molded body with reduced generation of molding cracks and reduced mechanical properties is obtained. Can be obtained.
The resin molded body of the present embodiment has a use as a resin molded body for chemical liquid tubes and the like used in the semiconductor field.

[Composite resin particles]
Hereinafter, the composite resin particle which is one embodiment to which the present invention is applied will be described.
The composite resin particle of this embodiment contains PTFE derived from fine powder and a carbon nanomaterial. The composite resin particles preferably have the carbon nanomaterial uniformly attached to the fine powder.

The composite resin particles of the present embodiment have the following aspects.
A composite resin particle comprising PTFE derived from fine powder and a carbon nanomaterial, wherein the composite resin particle has a volume resistivity of 1.0 × 10 ⁹ Ω · cm or less.

  The PTFE content of the composite resin particles of the present embodiment is preferably 98 to 99.8% by mass with respect to 100% by mass of the composite resin particles. If the content of PTFE is equal to or higher than the lower limit, the mechanical strength, heat resistance, flexibility and the like of the composite resin particles of this embodiment are likely to be excellent. If content of PTFE is below the said upper limit, the moldability of the composite resin particle of this embodiment will be easy to be excellent.

  The content of the carbon nanomaterial in the composite resin particles of the present embodiment is preferably 0.01 to 0.5% by mass with respect to 100% by mass of the composite resin particles. When the content of the carbon nanomaterial is equal to or higher than the lower limit, the conductivity of the composite resin particle of the present embodiment is easily excellent. If content of a carbon nanomaterial is below the said upper limit, the physical property derived from PTFE of the composite resin particle of this embodiment will be hard to be impaired. In addition, the composite resin particle of this embodiment can contain a well-known dispersing agent etc. as an arbitrary component.

The volume resistivity of the composite resin particles of the present embodiment is 1.0 × 10 ⁹ Ω · cm or less, preferably 10 ⁷ Ω · cm or less, and more preferably 10 ⁵ Ω · cm or less. . When the volume resistivity is 1.0 × 10 ⁹ Ω · cm or less, the conductivity of the molded body obtained from the composite resin particles of the present embodiment is easily excellent.

  The composite resin particles of the present embodiment can be produced according to the description in the section “[Production method of composite resin particles]” of the present embodiment described above.

As mentioned above, although embodiment of this invention was explained in full detail, this invention is not limited to this specific embodiment. Moreover, addition, omission, substitution, and other modifications of the configuration may be added to the present invention within the scope of the gist of the present invention described in the claims.
The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, the ketone solvent may contain known solvents such as water and alcohol solvents as long as the effects of the present invention are not impaired.

<Example>
Hereinafter, the effects of the present invention will be described in detail with reference to Examples and Comparative Examples. The present invention is not limited to the contents of the following examples.

<Examples 1 and 2 and Comparative Example 1>
First, 5 g of PTFE fine powder and 20 g of MEK were placed in a beaker, and stirred using a magnetic stirrer while keeping the temperature of the MEK at 10 ° C. or lower by bathing the beaker. While stirring with a magnetic stirrer, using an ultrasonic disperser (“UH-50” manufactured by MST) under conditions of an output of 50 W and a frequency of 20 kHz, the crushing time of each example was changed as shown in Table 1. The PTFE fine powder was crushed in MEK to prepare a MEK resin slurry.

Next, a CNT dispersion liquid in which CNTs were dispersed in MEK so as to have a CNT concentration of 0.2% by mass was prepared. 1.25 g of the CNT dispersion was added to the MEK resin slurry prepared in the above crushing step. The mixture was stirred for 10 minutes using a magnetic stirrer to prepare a CNT composite resin slurry.
MEK in the CNT composite resin slurry was removed, and the slurry was dried to obtain CNT composite fluororesin powder (CNT content 0.05 mass%) as composite resin particles.
The volume resistivity of the CNT composite fluororesin powder obtained in Examples 1 and 2 was measured at a plurality of locations, and was 1.2 × 10 ^{7 to} 6.7 × 10 ⁷ Ω · cm.

  5 g of the obtained composite resin particles were filled in a mold, gradually pressurized by a molding machine (“manual 5 ton table press” manufactured by Sansho Industry Co., Ltd.), kept at a pressure of 40 MPa for 1 minute, and subjected to compression pre-molding. A composite fluororesin molded body (φ30 mm, thickness 3 mm) was obtained.

<Comparative Example 2>
A CNT composite fluororesin powder was produced in the same manner as in Example 1 except that the ice bath was not performed. The obtained CNT composite fluororesin powder was divided into a fiberized gel lump and powdery powder.
Although compression molding was carried out by filling the mold including the fiberized sample, the preform was not easily detached from the mold. The preform was forcibly removed and an evaluation sample was obtained.

"Volume resistivity"
The volume resistivity of the obtained CNT composite fluororesin molded product or the molded product of Comparative Example 2 was measured according to the following description.
The volume resistivity was measured using a resistivity meter (“Loresta GP MCP-T610 type” manufactured by Mitsubishi Chemical Analytech Co., Ltd., four-terminal method). The measurement results are shown in Table 1.

"Releasability from mold"
After compression pre-molding with a mold, the case where the preform was easily removed from the mold was evaluated as ◯, and the case where it was not easily detached was evaluated as x.

"Appearance uniformity"
The appearance uniformity of the obtained CNT composite fluororesin molded product or the molded product of Comparative Example 2 was determined according to the following description.
In visual inspection, the number of resin aggregates having a size of 1 mm or more is 5.0 / cm ² or less and the number of CNT aggregates having a size of 1 mm or more is 1.0 / cm ² It was determined that it was not good.

As shown in Table 1, the volume resistivity of the CNT composite fluorine-containing resin molded article of Example 1 is ^{1.39 × 10 2 Ω · cm~2.00 ×} 10 2 Ω · cm, Example 2 CNT the volume resistivity of the composite fluorine-containing resin molded article was ^{1.63 × 10 2 Ω · cm~2.90 ×} 10 2 Ω · cm. On the other hand, the volume resistivity of the CNT composite fluororesin molded body of Comparative Example 1 is 1.94 × 10 ² Ω · cm to 8.12 × 10 ³ Ω · cm, and the numerical value of the volume resistivity varies. The width was large. This suggested that the composite resin particles of Examples 1 and 2 had CNTs uniformly attached to the fine powder as compared with Comparative Example 1.

  As shown in Table 1, the appearance uniformity of the CNT composite fluororesin molded bodies of Examples 1 and 2 was good. On the other hand, in the CNT composite fluororesin molded bodies of Comparative Examples 1 and 2, compared with Examples 1 and 2, the aggregates were conspicuous and the appearance uniformity was poor. In Comparative Example 2, a fiberized gel-like lump was observed. From this, it was suggested that the physical properties of the fine powder were impaired in the CNT composite fluororesin molded body of Comparative Example 2.

  The method for producing composite resin particles of the present invention is highly applicable when applied to the production of a conductive fluororesin used in extrusion molding. Such a conductive fluororesin is used for extrusion molding, and is used in a chemical solution tube used for the purpose of preventing electrification in the semiconductor field.

Claims (6)

A first step of crushing fine powder containing polytetrafluoroethylene obtained by emulsion polymerization in the presence of a ketone solvent;
A second step of obtaining a composite resin particle dispersion by dispersing the pulverized fine powder and the carbon nanomaterial in the ketone solvent;
A third step of removing the ketone solvent from the composite resin particle dispersion to obtain composite resin particles,
In the first step, the fine powder is crushed to an average particle size of 50 μm or less, and the temperature of the ketone solvent is set to 20 ° C. or less.   2. The composite resin particle according to claim 1, wherein the concentration of the carbon nanomaterial is 0.01 to 0.5% by mass with respect to 100% by mass in total of the carbon nanomaterial and the fine powder. Manufacturing method.   The method for producing composite resin particles according to claim 1, wherein the ketone solvent contains at least one selected from the group consisting of methyl ethyl ketone, acetone, diethyl ketone, methyl propyl ketone, and cyclohexanone.   The said carbon nanomaterial is a carbon nanotube, The manufacturing method of the composite resin particle as described in any one of Claims 1-3 characterized by the above-mentioned.   The resin molded object shape | molded using the composite resin particle manufactured with the manufacturing method of the composite resin particle as described in any one of Claims 1-4. A composite resin particle comprising polytetrafluoroethylene derived from fine powder containing polytetrafluoroethylene obtained by emulsion polymerization, and a carbon nanomaterial,
Composite resin particles in which the volume resistivity of the composite resin particles is 1.0 × 10 ⁹ Ω · cm or less.